In economics and related disciplines, a transaction cost is a cost in making any economic trade when participating in a market.These individual actions are really trans-actions instead of either individual behavior or the 'exchange' of commodities. It is this shift from commodities and individuals to transactions and working rules of collective action that marks the transition from the classical and hedonic schools to the institutional schools of economic thinking. The shift is a change in the ultimate unit of economic investigation. The classic and hedonic economists, with their communistic and anarchistic offshoots, founded their theories on the relation of man to nature, but institutionalism is a relation of man to man. The smallest unit of the classic economists was a commodity produced by labor. The smallest unit of the hedonic economists was the same or similar commodity enjoyed by ultimate consumers. One was the objective side, the other the subjective side, of the same relation between the individual and the forces of nature. The outcome, in either case, was the materialistic metaphor of an automatic equilibrium, analogous to the waves of the ocean, but personified as 'seeking their level.' But the smallest unit of the institutional economists is a unit of activity – a transaction, with its participants. Transactions intervene between the labor of the classic economists and the pleasures of the hedonic economists, simply because it is society that controls access to the forces of nature, and transactions are, not the 'exchange of commodities,' but the alienation and acquisition, between individuals, of the rights of property and liberty created by society, which must therefore be negotiated between the parties concerned before labor can produce, or consumers can consume, or commodities be physically exchanged'. In economics and related disciplines, a transaction cost is a cost in making any economic trade when participating in a market. In Transaction Costs, Institutions and Economic Performance (1992), Douglass C. North argues that institutions, understood as the set of rules in a society, are key in the determination of transaction costs. In this sense, institutions that facilitate low transaction costs, boost economic growth. Douglass North states that there are four factors that comprise transaction costs – 'measurement,' 'enforcement,' 'ideological attitudes and perceptions,' and 'the size of the market.' Measurement refers to the calculation of the value of all aspects of the good or service involved in the transaction. Enforcement can be defined as the need for an unbiased third party to ensure that neither party involved in the transaction reneges on their part of the deal. These first two factors appear in the concept of ideological attitudes and perceptions, North's third aspect of transaction costs. Ideological attitudes and perceptions encapsulate each individual's set of values, which influences their interpretation of the world. The final aspect of transaction costs, according to North, is market size, which affects the partiality or impartiality of transactions. Transaction costs can be divided into three broad categories: